Control for loom letoff



May 10 1955 A. J. HERARD, JR

CONTROL FOR LooM LETOFF Filed March 9, 1954 "Illl""IIU'HIIUIIWH"Illllllllllllll' lll Mw. www@ ATTORNEY INVENTOR ARCHIBALDJ. HERARD JR.

Unite States Patent C CNTR'OL FR LOOM LETOFF Archibald J. Herardwlr.,Worcester, Mass., assignor to Crompton & Knowles Loom Works, Worcester,Mass., a corporation of' Massachusetts Application March 9, 1954, SerialNo. 414,971

11 Claims. (Cl. 139-111) This invention relates to controls for loomlet-off mechanisms and it is the general object of the invention toprovide means employing preferably rotatable friction means to engagesome part of the let-oll mechanism to serve as a brake to prevent itfrom paying olf warp incident to loom stoppage.

A let-olf mechanism in common use employs a train of gearing includingan escapement device one part of which oscillates so that another partthereof can turn to permit movement of the gearing and thus allow warpto be paid oif. It has been found that under certain conditions ot'operation stoppage of the loom will cause the oscillating part of theeseapement mechanism to have undesired movements when there is no needfor movement resulting in an excessive paying off of warp which reducesits tension below the permissible minimum.

lt has been proposed heretofore to prevent excess motion of theoscillating part of the escapement mechanism by the addition thercintoof a relatively heavy weight which acts during loom operation to dampenvibration of the oscillating part, and it has further been proposed toapply a brake to the weight or some part moving with it when the loomstops.

lt is an important object of the present invention to provide a brakemeans for the oscillating part of the escapement mechanism utilizing arotatable friction surface which due to successive engagements with saidpart will turn to present fresh surfaces thereof to the weight and thusreduce wear of the surface.

lt is a further object of the invention to mount friction ringsrotatably on an eccentric which is normally spaced from the weight innon-braking position but is rocked to move the rings against the weightincident to loom stoppage, engagement of the weight with the ringsturning the latter on the eccentric.

lt is another object of the invention to use friction such as leather orbrake material which is slightly compressible so that upon engagementwith the weight it will not only arrest oscillation of the latter butwill also due to its compressibility have a slight rolling relation withthe weight and turn to present fresh surfaces to the weight.

It is another object of the invention to provide a variation of theforegoing wherein the friction surface is on a rotatable roll mounted tomove against the weight upon loom stoppage and be turned on its axis dueto engagement with the weight.

ln order that the invention may be clearly understood reference is madeto the accompanying drawings which illustrate by way of example twoembodiments of the invention and in which:

Fig. 1 is a side elevation of the rear part of a loom having thepreferred form of the invention applied thereto,

Fig. 2 is an enlarged horizontal section on line 2 2,

Fig. l,

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Figs. 3 and 4 are vertical sections on lines 3-3 and 4 4, respectively,Fig. 2,

Fig. 5 is a vertical section on line 5 5, Fig. 4,

Fig. 6 is a fragmentary side elevation looking in the direction of arrow6, Fig. 2,

Fig. 7 is a diagrammatic View similar to Fig. 3, but showing theeccentric moved to braking position,

Fig. 8 is a diagrammatic View of electric circuits which may be utilizedto control means which are associated with the eccentric, and

Fig. 9 is a diagrammatic view similar to Fig. 4 showing a modiiied formof the invention.

Referring to Figs. l and 8, the loom frame 1 has a shipper shaft 2 and ashipper handle 3 thereon to control operation of the loom. A rod 8,shown diagrammatically in Fig. 8, extends rearwardly from handle 3 to anelectric switch S which may be of any approved construction. As shown inFig. 8 the shipper handle as shown in full lines in running or drivingposition with the switch will be closed, but when the loom is stoppedthe shipper handle will be moved to the dotted line position shown inFig. 8 with resultant opening of switch S.

Behind tl e loom is an upright 1) which together with the loom framesupports a channel iron 11 having a Vertical web 12 and top and bottomflanges 13 and 14, respectively. Secured to the llange 13 and extendingupwardly therefrom is a casing l5 containing a nest of gearingoperatively connected to the warp beam B which is journaled at 15 forrotation on a stand 17 secured to the upright 1li. The beam has securedthereto a sprocket wheel 18 meshing with a chain 19 engaging anadjustable idler 20 and then extending upwardly and around a sprocketwheel 21 rotatable on the casing 15. Fixed with respect to the sprocketwheel is a gear 22 which meshes with a pinion 23 rotatable on the casingand fixed with respect to another gear 24 which in turn meshes with apinion 2S.

The casing 15 supports an escapement means, designated generally at E,including an escapement wheel fixed with respect to and turning withpinion 2S and including also an oscillating member 31 the pallet ordouble pawl 32 of which cooperates with the wheel 3:6. The oscillatingmember 31 is pivoted to the casing 15 at 33 and has la part 34 thereofextending downwardly for attachment to a dampening weight 35. The latteris secured to the part 34 by a bolt 3o and is provided primarily todampen excess vibration of member 31. The pallet 32 and parts 34 and 35may be considered as the oscillating part ofthe escapement mechanism E.

The loom has 'a stationary warp guide roll 40 and `a whip roll 41mounted on a lever 42 the upper end of which is pivoted as at 43 to asmall support 44 lixed with respect to the casing 15. A connector 45attached at the lower end of lever 42 extends forwardly and is connectedto a lever 46 which in turn is connected to a lever 47 pivotally mountedon a stationary stand 48. The lever 47 is connected to the lower end ofan upwardly extending rod 49 having secured thereto a collar 56 toengage a brake member 51. The upper end of the rod 49 is surrounded by acompression spring 52 and passes through a guide stand 53 secured to thetop of the casing 15. The brake member 51 has a shoe 55 for engagementwith an arcuate brake 'ange 56 on the part 34 and concentric with axis33. The warp W extends from the beam B over the guide and whip rolls andthen forwardly to provide the upper and lower warp sheds Wl and W2,respectively.

In operation, when the warp tension is at or near 'the permissibleminimum the whip roll will be in rear position, to the left in Fig. 1,and the rod 49 will be down so that spring 52 can hold the shoe 55against the brake ange 56 and prevent oscillation of member 31. Theescapement wheel is thus held against rotation and the gearing and thechain 19 operatively connected to it are held stationary to preventangular movement of the warp beam. Consumption of the warp during theweaving increases its tension and the whip roll moves forwardly, theresult of which through connector and lever 46 causes upward motion ofrod 49 to cause movement of the shoe away from the flange 55. The member31 will then be free to oscillate to permit the beam to rotateclockwise, Fig. l, to pay of; sufficient warp to reduce the warptension. During the warp paying oif operation the oscillating part ofthe escapement mechanism rocks back and forth around the pivot 33 andthis rocking will bc arrested when the warp tension again approaches itspermissible minimum to allow the shoe 55 to engage the lange 56.

The channel iron 11 has secured thereto a unit U including a carrier 59provided with two bearings 60 and 61 which are located respectively infront and back positions as viewed in Fig. 1. These bearing memberssupport a shaft 62, to which is secured an elongated eccentric member 63extending closely adjacent to the path of oscillation of the weight 35.Ordinarily the eccentric will be disposed as shown in Fig. 3 during loomoperation.

The means for holding the eccentric in its normal nonarresting position,Fig. 3, during loom operation includes an electromagnetic device shownhere as a solenoid held in any approved manner to the forward bearing60. The solenoid is supported by a holder 71 having a plate 72, see Fig.2, bolted at 73 to the bearing 60 and includ ing a forward upright arm74 and a cross bar 75 extending over the solenoid and connected to adepending arm 76. The lower ends of the arms 74 and 76 extend part wayunder the solenoid as at 77, and the holder 71 fits the solenoid closelyenough to hold it in rigid position.

The solenoid has a core which is pivoted at 81 to a link 32 the lowerend of which is pivoted at S3 to an arm 84 which is freely rockable on astud 85 secured to a bearing 60, as by being pinned thereto at 86, seeFig. 6. The hub 87 of arm S4 receives one end 88 of a torsion spring 89surrounding stud 85 and having the other end 90 thereof extended into acollar 91 held in angularly adjusted position on the stud 85 by setscrew 92. The effect of the spring is to tend to turn the arm 84 in acounter-clockwise direction as viewed in Fig. 4, but the spring willordinarily be overpowered vby the solenoid which is energized duringloom operation. A second arm 93 is secured by set screw 94 to the shaft62 and has a pin 95 thereon extending into a slot 96 in the arm 84. Amanually controlled electric switch M is supported by the bearing 60 andhas a small handle 97 by which it can be moved temporarily from itsnormally open position to closed position.

Solenoid 70 and the switches S and M are electrically connected asindicated diagrammatically in Fig. 8. A source of electric power P suchas a transformer is connected by wire 99 to one side of the solenoid andthe other side of the latter is connected by a wire 100 to a pole 101 ofthe switch S. The other pole 102 of switch S is attached to butinsulated from the rod 8 and is connected to the opposite side of thepower source P by wire 103. The normally open switch M is in parallelwith the switch S by having its electrode 105 connected to wire 100 andhaving its other electrode 106 connected to wire 103. The solenoid 70and spring 89 and the parts associated with them serve as control meansfor the eccentric 63 and the latter, to be described more fullyhereinafter, may be considered to be a support means for parts to bedescribed movable about an axis toward and from the weight 35 and thepath in which it swings.

The letoff proper may be similar to letolis shown in several priorpatents, one of which No. 2,330,514 to Payne may be mentioned as anexample, and the eccentric 63 and parts connected to it may be similarto structure and circuits previously proposed and shown, for instance,in copending application Serial No. 399,452, filed December 2l, 1953, byLaraia and Sepavich. It is thought sui'icient for present purposes tostate that the escapement means E operates when the brake 51 is in thenon-braking position to permit the beam B to turn and that if underthese conditions the loom should be stopped there is likely to result asufficient vibration to cause undesired oscillation of the member 31which may result in paying off more warp than is desired.

The present invention relates more particularly to the part of thearresting means which has direct engagement with the weight 35. Twoforms are shown herein, the tirst and preferred of which utilizes theeccentric already described. The aim of the preferred form of theinvention is to provide a surface for the eccentric which shall berotatable thereon for the purpose of distributing wear of the surfaceand also to present new or fresh surfaces to the weight.

Referring particularly to Fig. 5 collars 110 and 111 are secured to theright and left hand ends, respectively, of the eccentric and held inadjusted position along the eccentric by set screws 112. Between thecollars are located circular friction members 113 alternating withspacers or washers 114. The members 113 are in the form of rings havingexternal surfaces 115 of circular shape and the collars 110 and 111 areso located that the friction members 113 are rotatable on the eccentricbut held against substantial endwise movement on it. The spacers are ofless diameter than the members 113 and do not engage the weight 35. Thesurfaces 11S may be considered collectively as presenting frictionsurface means rotatable about the eccentric which in turn serves assupport means movable toward and from the weight 35. The members 113are, however, individually rotatable on the eccentric and only thosewhich directly engage the weight will be acted upon to turn. The weight35 will ordinarily be an unfinished casting and will have a more or lessrough surface to be engaged by the members 113. The ring members 113 aremade of friction material which may also though not necessarily becompressible, such as leather or brake material.

When the loom is in operation and the shipper handle is in the drivingor running position the switch S will be closed as indicated in Fig. 8and the solenoid '70 will be energized so that the core 80 will beraised to hold arm 84 in its elevated position against the ac tion ofspring 89. When in this position arm 34 holds the arm 93 in the positionshown in Fig. 4 to maintain the eccentric 63 in the non-arrestingposition thereof shown in Fig. 3. As soon as the shipper handle isthrown to the off or stopping position, see dotted lines Fig. 8,electrode 102 moves away from electrode 101 and the circuit for thesolenoid is open, whereupon the spring 89 turns the arm 84 in acounter-clockwise direction, Fig. 4, to rock arm 93 in a clockwisedirection to turn the eccentric around its axis to the arrestingposition thereof against the weight 35 as shown diagrammatically in Fig.7. Engagement of the friction members 113 with the weight 35 will besufficient to arrest any oscillation of the member 31 which mightotherwise occur incident to stoppage of the loom, and the escapementmeans is prevented from operating, thus locking the beam B againstturning and maintaining a workable warp tension.

During engagement of the friction ring members 113 with the weight theyare moved bodily against the weight by a force derived partly from theweight of the core 80 and partly from the spring 89. From the time therings first engage the weight 35 until the eccentric comes to its nalposition there is a slight rolling motion of the rings on weight causingthe rings to turn in a counter-clockwise direction with respect to theeccentric as viewed in Fig. 7. This rotary motion of the rings is notfully undone when the eccentric is moved to its non-arresting positionshown in Fig. 3, as by closure of the switch M. Slow creepage of thering members 113 around the eccentric in a counter-clockwise directionas viewed in Fig. 7 can be demonstrated by placing a mark on the top ofone of the rings and then subjecting the eccentric to repeated movementsrst to braking or arresting position and then away from braking positionto non-arresting position. When the eccentric is subjected to suchalternating movements the mark will be observed to move away from theweight 35. This creeping of the rings 113 continually presents newsurfaces to the weight 35 so that the entire surface of any ring whichengages the Weight will eventually be presented to it so that wear willbe distributed entirely around the ring.

If the cause of loom stoppage requires that the letoff be released theoperator 'can close the switch M, whereupon the solenoid will bereenergized and the eccentric will be moved from the position shown inFig. 7 back to the non-arresting position shown in Fig. 4. Release ofthe handle 97 will result in opening the switch M, whereupon theeccentric will return to arresting position.

The modified form of the invention operates on the same generalprinciple as does the preferred form, but instead of an eccentric asimple roll is used. Referring to Fig. 9, the unit Ua includes a carrierbolted at 126 to channel iron 11 and formed with depending bearing arms127 and 128 which support a shaft 129 rockable in the bearing arms.cured to shaft 129 have rotatably mounted on their upper ends a roll 132to which is secured a friction surface 133 for engagement with weight35. The arms and 131 constitute means movable about an axis toward andfrom weight 35 and the path in which it swings.

A shelf 135 on arm 127 supports a solenoid 136, similar to solenoid 70,having a core 137 connected by link 138 to arm 130. The latter arm isconnected to a tension spring 140 the upper end of which is held to theshelf. Solenoid 136 is controlled electrically as is solenoid 70 andnormally is energized to hold roll 132 in non-arresting position awayfrom weight 35 against the action of spring 140, and the latter, upondeenergization of solenoid 136, causes the roll 132 to move to arrestingposition against the weight. The roll is free to turn on the arms 130and 131 and rotates around its axis as do the ring members 113.

From the foregoing it will be seen that the invention sets forth meansfor arresting undesired oscillation of the member 34 by friction meansrotatable on a support means to present fresh friction surfaces to theWeight 35. It will also be seen that the collars 110 and 111 used in thepreferred form effectively prevent endwise movement of the rings 113 onthe eccentric but permit them to rotate. In the modified form thefriction surface is on a roll which is free to rotate. In both forms thefriction part or parts, as the rings 113 or roll 132, are rotatable onsupport means, as the eccentric or arms 130 and 131, which are movabletoward and from the weight 35 and its path of oscillation, the weightbeing engaged by parts of the friction surface which move in a pathoblique to the weight path at the time of contact with the weight. Theoblique path need not be arcuate as shown herein. The friction surfacesare of material which is preferably though not necessarily slightlycompressible. The compressibility, when present, is thought to assist inthe rolling of the rings and roll 132 along the Weight, and that thisrolling contributes to the slow rotary creep- Arms 130 and 131 se- (rtling of the friction surface with respect to its support. The inventionalso sets forth units, as U and Ua, readily adaptable to existing looms.

Having now particularly described and ascertained the nature of theinvention and in what manner the same is to be performed, what isclaimed is:

l. In let-off mechanism for a loom having a warp beam and whereinoscillation of a part of an escapement means enables the beam to turn topay off warp, support means movable toward and from said part of theescapement means to assume arresting and non-arresting positions withrespect to said part, friction means for engagement with said partrotatable on said movable support means, and control means for saidmovable support means effective to keep the latter in the non-arrestingposition thereof during loom operation to enable said part to oscillatebut effecting movement of the movable support means to the arrestingposition thereof to move said friction means against said part toprevent oscillation thereof when the loom is stopped, said frictionmeans due to engagement with said part tending to turn on said movablesupport means to present different parts thereof to said part of theescapement means.

2. The let-off mechanism set forth in claim 1 wherein the support meansis an elongated member and the friction means is in the form of aplurality of rings rotatable on the member. y

3. The let-off mechanism set forth in claim l wherein the support meansis an elongated member and the friction means are rings rotatable on themember separated from each other by spacers on the elongated member.

4. The let-off mechanism set forth in claim l wherein the support meansis an elongated member having collars secured to the ends thereof inadjusted longitudinal position thereon and the friction means are ringsrotatable on the member between said collars and held againstsubstantial endwise movement along the member by said collars.

5. The let-olf mechanism set forth in claim 1 wherein the support meansis an elongated member having collars secured to the ends thereof inadjusted lengthwise position relative to the member and the frictionmeans are rings rotatable on the member between said collars alternatingwith spacers of less diameter on the elongated member, the spacersholding the rings in spaced relation along the member and cooperatingwith the collars to prevent substantial movement of the rings lengthwiseof the member.

6. The let-off mechanism set forth in claim 1 wherein the support meansjust prior to engagement of the friction means with said part causes thesurface of the friction means which is to engage said part to move in adirection oblique to said part.

7. In a let-off mechanism set forth in claim 1 wherein the frictionmeans is compressible and is subjected to compression at those partsthereof which engage said part of the escapement means when the supportmeans moves to arresting position.

8. In a let-olf mechanism set forth in claim l wherein the support meanscomprises arms mounted for movement in unison with respect to said partof the escapement means and the friction means in a roll rotatable onsaid arms.

9. A unit to control the oscillating part of an escapement means of awarp let-off mechanism, said unit including a carrier, support meansmounted for angular movement on said carrier, an electromagnetic devicesupported on the carrier, means whereby energization of the deviceeffects turning of the support means in one direction with respect tothe carrier, other means supported by the carrier tending to turn saidsupport means in the opposite direction, and friction means mounted onthe support means for rotation with respect thereto.

10. The unit set forth in claim 9 wherein the support means is anelongated eccentric and the friction means are rings rotatable on theeccentric and said other means References Cited in the file of thispatent is effective upon deenergization of the electromagnetic UNITEDSTATES PATENTS device to rock said eccentric in said opposite direction.

comprises a roll rotatable 0n said arms.

